HOLD IT: Larry King was asked by CNN to stay through end of year. (AP)

CNN is asking Larry King to postpone his final show — slated for fall — and stick around until the end of the year, The Post has learned.

British journalist and “America’s Got Talent” judge Piers Morgan, who is widely thought to be King’s replacement, is apparently having trouble obtaining a work visa, according to several sources.

It is uncertain how serious the glitch is — but it has apparently held up the long-awaited deal to put Morgan in King’s chair by late October or early November.

It is not believed that CNN has had a change of heart about giving the controversial Morgan, 45, one of the most sought-after spots on American TV.

As a British citizen, Morgan needs a special visa that will allow him to work full-time in the US — and those types of visas are increasingly difficult to get, according to lawyers who specialize in the field.

In general, the process “has gotten much slower in the past year” as the federal government tightens paperwork requirements for immigrants, says one attorney.

Because Morgan appears on “America’s Got Talent” only during the summer, he could get by with a limited visa that permits him to work here a specified number of days per year. The trouble has come as he tried to upgrade the visa.

When King announced last July that he was leaving, he said that he told CNN officials, “I would like to end ‘Larry King Live,’ the nightly show, this fall and CNN has graciously accepted.”

A CNN spokesman yesterday declined to comment about King extending his stay. Because “no date has been announced yet, there’s nothing specific at this point,” the rep said in an e-mail.

Reports that an official announcement of Morgan’s appointment taking over for King was “just days away” have been buzzing around for weeks.

And it is still possible a last-minute hitch could send CNN back to the drawing board, looking for a new 9 p.m. host for its ailing primetime lineup.

But that does not appear likely yet.

The sly, former newspaper editor from London was a surprise choice for the job of replacing King, a fixture of American TV for as long as most people can remember.

King — who has made it clear that Morgan would not have been his first choice — is said to have jumped at the chance to extend his stay, according to sources.